Difference between revisions of "Team:Fudan-TSI/Basic Part"

(LC after)
m
 
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−
{{Fudan-TSI}}
+
{{Fudan-TSI}}<!-- jquery loaded by HQ 1.12.4 -->
 
<html></p></div></div></div><meta name="viewport" content="width=device-width, initial-scale=1"><meta charset="UTF-8">
 
<html></p></div></div></div><meta name="viewport" content="width=device-width, initial-scale=1"><meta charset="UTF-8">
 
   <link rel="stylesheet" href="https://2019.igem.org/wiki/index.php?title=Template:Fudan-TSI/materialize.css&action=raw&ctype=text/css">
 
   <link rel="stylesheet" href="https://2019.igem.org/wiki/index.php?title=Template:Fudan-TSI/materialize.css&action=raw&ctype=text/css">
Line 108: Line 108:
 
</div><!-- #pageCover -->
 
</div><!-- #pageCover -->
 
<script src="https://2019.igem.org/wiki/index.php?title=Template:Fudan-TSI/bkg&action=raw&ctype=text/javascript"></script>
 
<script src="https://2019.igem.org/wiki/index.php?title=Template:Fudan-TSI/bkg&action=raw&ctype=text/javascript"></script>
−
<script>function bkgFunction(e){if(e){var t=new Stats;t.domElement.style.position="absolute",t.domElement.style.left="0",t.domElement.style.top="0",document.body.appendChild(t.domElement),requestAnimationFrame(function e(){t.update(),requestAnimationFrame(e)})}var n=document.getElementById("demo");tesselation.setup(n),gradients.setup();var o,r=1e4,a=3e3;window.requestAnimationFrame(function e(t){(!o||r<t-o)&&(o=t,tesselation.next(a),gradients.next(a)),window.requestAnimationFrame(e)})}var calcDelaunayTriangulation=function(){var E=1/1048576;function p(e,t,n,o){var r,a,i,l,c,u,s,d,h,f,p=e[t][0],m=e[t][1],g=e[n][0],y=e[n][1],w=e[o][0],I=e[o][1],b=Math.abs(m-y),v=Math.abs(y-I);if(b<E&&v<E)throw new Error("Can't get circumcircle since all 3 points are y-aligned");return i=-(g-p)/(y-m),l=-(w-g)/(I-y),c=(p+g)/2,u=(g+w)/2,s=(m+y)/2,d=(y+I)/2,{i:t,j:n,k:o,x:r=b<E?c:v<E?u:(i*c-l*u+d-s)/(i-l),y:a=v<b?i*(r-c)+s:l*(r-u)+d,r:(h=g-r)*h+(f=y-a)*f}}function m(e){var t,n,o,r,a,i;for(n=e.length;n;)for(r=e[--n],o=e[--n],t=n;t;){if(i=e[--t],o===(a=e[--t])&&r===i){e.splice(n,2),e.splice(t,2);break}if(o===i&&r===a){e.splice(n,2),e.splice(t,2);break}}}return function(n){var e,t,o,r,a,i,l,c,u,s,d,h,f=n.length;if(f<3||2e3<f)return[];for(n=n.slice(0),o=new Array(f),e=f;e--;)o[e]=e;for(o.sort(function(e,t){return n[t][0]-n[e][0]}),r=function(e){var t,n,o,r,a,i,l=Number.POSITIVE_INFINITY,c=Number.POSITIVE_INFINITY,u=Number.NEGATIVE_INFINITY,s=Number.NEGATIVE_INFINITY;for(t=e.length;t--;)e[t][0]<l&&(l=e[t][0]),e[t][0]>u&&(u=e[t][0]),e[t][1]<c&&(c=e[t][1]),e[t][1]>s&&(s=e[t][1]);return o=s-c,[[(a=l+.5*(n=u-l))-20*(r=Math.max(n,o)),(i=c+.5*o)-r],[a,i+20*r],[a+20*r,i-r]]}(n),n.push(r[0],r[1],r[2]),a=[p(n,f+0,f+1,f+2)],i=[],l=[],e=o.length;e--;l.length=0){for(h=o[e],t=a.length;t--;)0<(c=n[h][0]-a[t].x)&&c*c>a[t].r?(i.push(a[t]),a.splice(t,1)):c*c+(u=n[h][1]-a[t].y)*u-a[t].r>E||(l.push(a[t].i,a[t].j,a[t].j,a[t].k,a[t].k,a[t].i),a.splice(t,1));for(m(l),t=l.length;t;)d=l[--t],s=l[--t],a.push(p(n,s,d,h))}for(e=a.length;e--;)i.push(a[e]);for(a.length=0,e=i.length;e--;)i[e].i<f&&i[e].j<f&&i[e].k<f&&a.push(i[e].i,i[e].j,i[e].k);return a}}(),tesselation=function(){var a,h,f,i;return{setup:function(e){var t=(a=e).getAttribute("viewBox").split(/\D/g);h=t[2],f=t[3]},next:function(e){var t,n,o;if(e/=1e3,i&&i.children&&i.children.length){for(n=o=(t=i).children.length;n--;)TweenMax.to(t.children[n],.4*e,{opacity:0,delay:e*(.3*n/o)});TweenMax.delayedCall(.75*e,function(e){a.removeChild(e)},[t],this)}var r=function(){var e,t,n,o,r=window.innerWidth,a=window.innerHeight,i=[],l=h%(e=h/f<r/a?250*h/r:250*f/a)/2,c=f%e/2;for(n=Math.floor(h/e)+1;-1<=n;n--)for(o=Math.floor(f/e)+1;-1<=o;o--)i.push([l+e*(n+.75*(Math.random()-.5)),c+e*(o+.75*(Math.random()-.5))]);var u,s=calcDelaunayTriangulation(i),d=document.createElementNS("http://www.w3.org/2000/svg","g");for(t=s.length;t;)(u=document.createElementNS("http://www.w3.org/2000/svg","polygon")).setAttribute("points",i[s[--t]][0]+","+i[s[t]][1]+" "+i[s[--t]][0]+","+i[s[t]][1]+" "+i[s[--t]][0]+","+i[s[t]][1]),d.appendChild(u);return d}();for(n=o=r.children.length;n--;)TweenMax.fromTo(r.children[n],.4*e,{opacity:0},{opacity:.3+.25*Math.random(),delay:e*(.3*n/o+.3),ease:Back.easeOut});a.appendChild(r),i=r}}}(),gradients=function(){var o,r,a,i=["#3c6df0","#12a3b4","#00a78f","#00aa5e","#81b532","#e3bc13","#ffb000","#fe8500","#fe6100","#e62325","#dc267f","#c22dd5","#9753e1","#5a3ec8"];return{setup:function(){a=!1,o={stopA:document.getElementById("stop1a"),stopB:document.getElementById("stop1b"),rect:document.getElementById("rect1")},r={stopA:document.getElementById("stop2a"),stopB:document.getElementById("stop2b"),rect:document.getElementById("rect2")},o.rect.style.opacity=0,r.rect.style.opacity=0},next:function(e){var t,n;e/=1e3,t=a?(n=o,r):(n=r,o),a=!a,TweenMax.to(n.rect,.55*e,{opacity:0,delay:.2*e,ease:Sine.easeOut}),function(e){var t=Math.floor(i.length*Math.random()),n=Math.floor(3*Math.random())+3;n=(t+n*(Math.random()<.5?-1:1)+i.length)%i.length,e.stopA.setAttribute("stop-color",i[t]),e.stopB.setAttribute("stop-color",i[n])}(t),TweenMax.to(t.rect,.65*e,{opacity:1,ease:Sine.easeIn})}}}();bkgFunction();
+
        <script>
−
</script>
+
      //////////////////////////////
 +
      // Demo Functions
 +
      //////////////////////////////
 +
      function bkgFunction(showStats) {
 +
        // stats
 +
        if (showStats) {
 +
        var stats = new Stats();
 +
        stats.domElement.style.position = 'absolute';
 +
        stats.domElement.style.left = '0';
 +
        stats.domElement.style.top = '0';
 +
        document.body.appendChild(stats.domElement);
 +
        requestAnimationFrame(function updateStats(){
 +
          stats.update();
 +
          requestAnimationFrame(updateStats);
 +
        });
 +
        }
 +
        // init
 +
        var svg = document.getElementById('demo');
 +
        tesselation.setup(svg);
 +
        gradients.setup();
 +
        var lastTransitionAt, transitionDelay = 10000, transitionDuration = 3000;
 +
        function playNextTransition() {
 +
        tesselation.next(transitionDuration);
 +
        gradients.next(transitionDuration);
 +
        };
 +
        function tick(time) {
 +
        if (!lastTransitionAt || time - lastTransitionAt > transitionDelay) {
 +
          lastTransitionAt = time;
 +
          playNextTransition();
 +
        }
 +
        window.requestAnimationFrame(tick);
 +
        }
 +
        window.requestAnimationFrame(tick);
 +
      }
 +
      //////////////////////////////
 +
      // Delaunay Triangulation
 +
      //////////////////////////////
 +
      var calcDelaunayTriangulation = (function() {
 +
        var EPSILON = 1.0 / 1048576.0;
 +
        function getSuperT(vertices) {
 +
        var xMin = Number.POSITIVE_INFINITY, yMin = Number.POSITIVE_INFINITY,
 +
          xMax = Number.NEGATIVE_INFINITY, yMax = Number.NEGATIVE_INFINITY,
 +
          i, xDiff, yDiff, maxDiff, xCenter, yCenter;
 +
        for(i = vertices.length; i--; ) {
 +
          if(vertices[i][0] < xMin) xMin = vertices[i][0];
 +
          if(vertices[i][0] > xMax) xMax = vertices[i][0];
 +
          if(vertices[i][1] < yMin) yMin = vertices[i][1];
 +
          if(vertices[i][1] > yMax) yMax = vertices[i][1];
 +
        }
 +
        xDiff = xMax - xMin;
 +
        yDiff = yMax - yMin;
 +
        maxDiff = Math.max(xDiff, yDiff);
 +
        xCenter = xMin + xDiff * 0.5;
 +
        yCenter = yMin + yDiff * 0.5;
 +
        return [
 +
          [xCenter - 20 * maxDiff, yCenter - maxDiff],
 +
          [xCenter, yCenter + 20 * maxDiff],
 +
          [xCenter + 20 * maxDiff, yCenter - maxDiff]
 +
        ];
 +
        }
 +
        function circumcircle(vertices, i, j, k) {
 +
        var xI = vertices[i][0], yI = vertices[i][1],
 +
          xJ = vertices[j][0], yJ = vertices[j][1],
 +
          xK = vertices[k][0], yK = vertices[k][1],
 +
          yDiffIJ = Math.abs(yI - yJ), yDiffJK = Math.abs(yJ - yK),
 +
          xCenter, yCenter, m1, m2, xMidIJ, xMidJK, yMidIJ, yMidJK, xDiff, yDiff;
 +
        // bail condition
 +
        if(yDiffIJ < EPSILON){
 +
          if (yDiffJK < EPSILON){
 +
            throw new Error("Can't get circumcircle since all 3 points are y-aligned");
 +
          }
 +
        }
 +
 
 +
 
 +
        // calc circumcircle center x/y, radius
 +
        m1  = -((xJ - xI) / (yJ - yI));
 +
        m2  = -((xK - xJ) / (yK - yJ));
 +
        xMidIJ = (xI + xJ) / 2.0;
 +
        xMidJK = (xJ + xK) / 2.0;
 +
        yMidIJ = (yI + yJ) / 2.0;
 +
        yMidJK = (yJ + yK) / 2.0;
 +
        xCenter = (yDiffIJ < EPSILON) ? xMidIJ :
 +
          (yDiffJK < EPSILON) ? xMidJK :
 +
          (m1 * xMidIJ - m2 * xMidJK + yMidJK - yMidIJ) / (m1 - m2);
 +
        yCenter  = (yDiffIJ > yDiffJK) ?
 +
          m1 * (xCenter - xMidIJ) + yMidIJ :
 +
          m2 * (xCenter - xMidJK) + yMidJK;
 +
        xDiff = xJ - xCenter;
 +
        yDiff = yJ - yCenter;
 +
        // return
 +
        return {i: i, j: j, k: k, x: xCenter, y: yCenter, r: xDiff * xDiff + yDiff * yDiff};
 +
        }
 +
        function dedupeEdges(edges) {
 +
        var i, j, a, b, m, n;
 +
        for(j = edges.length; j; ) {
 +
          b = edges[--j]; a = edges[--j];
 +
          for(i = j; i; ) {
 +
          n = edges[--i]; m = edges[--i];
 +
          if(a === m){
 +
            if (b===n){
 +
              edges.splice(j, 2); edges.splice(i, 2);
 +
              break;
 +
            }
 +
          }
 +
          if(a === n){
 +
            if (b===m){
 +
              edges.splice(j, 2); edges.splice(i, 2);
 +
              break;
 +
            }
 +
          }
 +
          }
 +
        }
 +
        }
 +
        return function(vertices) {
 +
        var n = vertices.length,
 +
          i, j, indices, st, candidates, locked, edges, dx, dy, a, b, c;
 +
        // bail if too few / too many verts
 +
        if(n < 3 || n > 2000)
 +
          return [];
 +
        // copy verts and sort indices by x-position
 +
        vertices = vertices.slice(0);
 +
        indices = new Array(n);
 +
        for(i = n; i--; )
 +
          indices[i] = i;
 +
        indices.sort(function(i, j) {
 +
          return vertices[j][0] - vertices[i][0];
 +
        });
 +
        // supertriangle
 +
        st = getSuperT(vertices);
 +
        vertices.push(st[0], st[1], st[2]);
 +
        // init candidates/locked tris list
 +
        candidates = [circumcircle(vertices, n + 0, n + 1, n + 2)];
 +
        locked = [];
 +
        edges = [];
 +
        // scan left to right
 +
        for(i = indices.length; i--; edges.length = 0) {
 +
          c = indices[i];
 +
          // check candidates tris against point
 +
          for(j = candidates.length; j--; ) {
 +
          // lock tri if point to right of circumcirc
 +
          dx = vertices[c][0] - candidates[j].x;
 +
          if (dx > 0.0){
 +
            if(dx * dx > candidates[j].r){
 +
              locked.push(candidates[j]);
 +
            candidates.splice(j, 1);
 +
            continue;
 +
            }
 +
          }
 +
 
 +
 
 +
          // point outside circumcirc = leave candidates
 +
          dy = vertices[c][1] - candidates[j].y;
 +
          if(dx * dx + dy * dy - candidates[j].r > EPSILON)
 +
            continue;
 +
          // point inside circumcirc = break apart, save edges
 +
          edges.push(
 +
            candidates[j].i, candidates[j].j,
 +
            candidates[j].j, candidates[j].k,
 +
            candidates[j].k, candidates[j].i
 +
          );
 +
          candidates.splice(j, 1);
 +
          }
 +
          // new candidates from broken edges
 +
          dedupeEdges(edges);
 +
          for(j = edges.length; j; ) {
 +
          b = edges[--j];
 +
          a = edges[--j];
 +
          candidates.push(circumcircle(vertices, a, b, c));
 +
          }
 +
        }
 +
        // close candidates tris, remove tris touching supertri verts
 +
        for(i = candidates.length; i--; )
 +
          locked.push(candidates[i]);
 +
        candidates.length = 0;
 +
        for(i = locked.length; i--; )
 +
          if(locked[i].i < n){
 +
            if(locked[i].j < n){
 +
              if(locked[i].k < n){
 +
                candidates.push(locked[i].i, locked[i].j, locked[i].k);
 +
              }
 +
            }
 +
          }
 +
 
 +
 
 +
        // done
 +
        return candidates;
 +
        };
 +
      })();
 +
      var tesselation = (function() {
 +
        var svg, svgW, svgH, prevGroup;
 +
        function createRandomTesselation() {
 +
        var wW = window.innerWidth;
 +
        var wH = window.innerHeight;
 +
        var gridSpacing = 250, scatterAmount = 0.75;
 +
        var gridSize, i, x, y;
 +
        if (wW / wH > svgW / svgH) { // window wider than svg = use width for gridSize
 +
          gridSize = gridSpacing * svgW / wW;
 +
        } else { // window taller than svg = use height for gridSize
 +
          gridSize = gridSpacing * svgH / wH;
 +
        }
 +
        var vertices = [];
 +
        var xOffset = (svgW % gridSize) / 2, yOffset = (svgH % gridSize) / 2;
 +
        for (x = Math.floor(svgW/gridSize) + 1; x >= -1; x--) {
 +
          for (y = Math.floor(svgH/gridSize) + 1; y >= -1; y--) {
 +
          vertices.push(
 +
            [
 +
            xOffset + gridSize * (x + scatterAmount * (Math.random() - 0.5)),
 +
            yOffset + gridSize * (y + scatterAmount * (Math.random() - 0.5))
 +
            ]
 +
          );
 +
          }
 +
        }
 +
        var triangles = calcDelaunayTriangulation(vertices);
 +
        var group = document.createElementNS('http://www.w3.org/2000/svg','g');
 +
        var polygon;
 +
        for(i = triangles.length; i; ) {
 +
          polygon = document.createElementNS('http://www.w3.org/2000/svg','polygon');
 +
          polygon.setAttribute('points',
 +
          vertices[triangles[--i]][0] + ',' + vertices[triangles[i]][1] + ' ' +
 +
          vertices[triangles[--i]][0] + ',' + vertices[triangles[i]][1] + ' ' +
 +
          vertices[triangles[--i]][0] + ',' + vertices[triangles[i]][1]
 +
          );
 +
          group.appendChild(polygon);
 +
        }
 +
        return group;
 +
        }
 +
        return {
 +
        setup: function(svgElement) {
 +
          svg = svgElement;
 +
          var vb = svg.getAttribute('viewBox').split(/\D/g);
 +
          svgW = vb[2];
 +
          svgH = vb[3];
 +
        },
 +
        next: function(t) {
 +
          var toRemove, i, n;
 +
          t /= 1000;
 +
          if(prevGroup){
 +
            if(prevGroup.children){
 +
              if(prevGroup.children.length){
 +
                toRemove = prevGroup;
 +
                n = toRemove.children.length;
 +
                for (i = n; i--; ) {
 +
                  TweenMax.to(toRemove.children[i], t*0.4, {opacity: 0, delay: t*(0.3*i/n)});
 +
                }
 +
                TweenMax.delayedCall(t * (0.7 + 0.05), function(group) { svg.removeChild(group); }, [toRemove], this);
 +
              }
 +
            }
 +
          }
 +
 
 +
          var g = createRandomTesselation();
 +
          n = g.children.length;
 +
          for (i = n; i--; ) {
 +
          TweenMax.fromTo(g.children[i], t*0.4, {opacity: 0}, {opacity: 0.3 + 0.25 * Math.random(), delay: t*(0.3*i/n + 0.3), ease: Back.easeOut});
 +
          }
 +
          svg.appendChild(g);
 +
          prevGroup = g;
 +
        }
 +
        }
 +
      })();
 +
      //////////////////////////////
 +
      // Gradients
 +
      //////////////////////////////
 +
      var gradients = (function() {
 +
        var grad1, grad2, showingGrad1;
 +
        // using colors from IBM Design Colors this time
 +
        var colors = [ // 14 colors - use 3-5 span
 +
        '#3c6df0', // ultramarine50
 +
        '#12a3b4', // aqua40
 +
        '#00a78f', // teal40
 +
        '#00aa5e', // green40
 +
        '#81b532', // lime30
 +
        '#e3bc13', // yellow20
 +
        '#ffb000', // gold20
 +
        '#fe8500', // orange30
 +
        '#fe6100', // peach40
 +
        '#e62325', // red50
 +
        '#dc267f', // magenta50
 +
        '#c22dd5', // purple50
 +
        '#9753e1', // violet50
 +
        '#5a3ec8'  // indigo60
 +
        ];
 +
        function assignRandomColors(gradObj) {
 +
        var rA = Math.floor(colors.length * Math.random());
 +
        var rB = Math.floor(Math.random() * 3) + 3; // [3 - 5]
 +
        rB = (rA + (rB * (Math.random() < 0.5 ? -1 : 1)) + colors.length) % colors.length;
 +
        gradObj.stopA.setAttribute('stop-color', colors[rA]);
 +
        gradObj.stopB.setAttribute('stop-color', colors[rB]);
 +
        }
 +
        return {
 +
        setup: function() {
 +
          showingGrad1 = false;
 +
          grad1 = {
 +
          stopA: document.getElementById('stop1a'),
 +
          stopB: document.getElementById('stop1b'),
 +
          rect: document.getElementById('rect1')
 +
          };
 +
          grad2 = {
 +
          stopA: document.getElementById('stop2a'),
 +
          stopB: document.getElementById('stop2b'),
 +
          rect: document.getElementById('rect2')
 +
          };
 +
          grad1.rect.style.opacity = 0;
 +
          grad2.rect.style.opacity = 0;
 +
        },
 +
        next: function(t) {
 +
          t /= 1000;
 +
          var show, hide;
 +
          if (showingGrad1) {
 +
          hide = grad1;
 +
          show = grad2;
 +
          } else {
 +
          hide = grad2;
 +
          show = grad1;
 +
          }
 +
          showingGrad1 = !showingGrad1;
 +
          TweenMax.to(hide.rect, 0.55*t, {opacity: 0, delay: 0.2*t, ease: Sine.easeOut});
 +
          assignRandomColors(show);
 +
          TweenMax.to(show.rect, 0.65*t, {opacity: 1, ease: Sine.easeIn});
 +
        }
 +
        };
 +
      })();
 +
      //////////////////////////////
 +
      // Start
 +
      //////////////////////////////
 +
      bkgFunction();
 +
    </script>
 
               <div style="position:absolute;top:100px;left:9%"><center><img style="height:120px;width:auto" alt="cover gif 1st added" src="https://static.igem.org/mediawiki/2019/8/81/T--Fudan-TSI--coverBasicParts.gif" /></center></div>
 
               <div style="position:absolute;top:100px;left:9%"><center><img style="height:120px;width:auto" alt="cover gif 1st added" src="https://static.igem.org/mediawiki/2019/8/81/T--Fudan-TSI--coverBasicParts.gif" /></center></div>
 
           </div>
 
           </div>

Latest revision as of 05:54, 16 November 2019

Basic Parts | 2019 iGEM Team:Fudan-TSI


Basic Parts

cover gif 1st added

When the organization has once begun to vary, it generally continues varying for many generations. – Charles Darwin, The Origin of Life

Best basic part

As best basic part we’d like to present the Moloney Murine Leukemia Virus Reverse Transcriptase (MMLV-RT) BBa_K3257042. MMLV-RT is responsible for the reverse transcription process of the target Gene of Interest (GOI), which is rather one of the most important processes in our system.

Naturally, when Moloney Murine Leukemia Virus (MMLV) infects its host, gag-pol polyprotein encoded in the MMLV genome is expressed. This polyprotein will be further cleaved into the capsid protein (about 60.4kDa) and the reverse transcriptase (about 69.1kDa) by a protease (about 13.5 kDa) also encoded in the polyprotein mRNA (Figure A).

Figure A. Exhibition of gene encoding gag-pol polyprotein.

MMLV-RT acts as a reverse transcription tool with a relatively low fidelity so that it is qualified for a random mutation generator. Also, Zhang et al. showed that point mutation (nucleotide from A to T) of at the 586th amino acid residual (from Y to F) of the polymerase itself (encoded merely by pol gene, BBa_K3257043), further improves its error-prone nature by ≈5-fold in a single replication cycle.

MMLV-RT was first designed to be transcribed into a single mRNA with a stop codon between the gag gene (encoding capsid protein) and pol gene (encoding the reverse transcriptase), which could not be properly expressed in vivo (of E. coli) when we fused an EGFP after the gag-pol CDS.

Frustratedly, we set out to solve the problem by cloning it into various kinds of vectors, after different promoters, and mutating the stop codon between gag and pol into Glutamine (from T to C), an intermediate amino acid residual as a read-through. (In wild type Moloney Murine Leukemia virus , there is a stop codon between mRNA transcribed from the gag gene and pol gene while it can be read through as a Glutamine when translated by ribosome to form gag and gag-pol polyprotein at a ratio of 20:1. We have changed the stop codon into a Glutamine codon to assure its readability in E. coli.)

Using SDS-PAGE and qRT-PCR, we have verified its expression in E. coli (Figure A) and its function as a reverse transcriptase (Figure B). Furthermore, its mutation rate is able to be measured by high throughput sequencing. In the future, this part can be used to express gag-pol polyprotein inside the bacteria to initiate the reverse transcription process in vivo.

Figure B. gag-pol polyprotein is successfully expressed and underwent excision in the cell.

For more information of other basic parts, please refer to the part collection page and the iGEM Part Registry ranging from BBa_K3257000 to BBa_K3257076.

Reference

  1. [1] Zhang W H, Svarovskaia E S, Barr R, et al. Y586F mutation in murine leukemia virus reverse transcriptase decreases fidelity of DNA synthesis in regions associated with adenine-thymine tracts. Proceedings of the National Academy of Sciences, 2002, 99(15):10090-10095.